Machine tool



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MACHINE TOOL Filed Dec. 2, 1957 17 Smeets-ShevaV 17 Afl/.50v I I ma q wwdden Patented Aug. 12, 1.941

iJNiTED STATE s PATENT 1 artisti MACHINE Tool.

Ira J. Snade'r, Detroit, Mich., assignor to Eir- Celi-O Corporation, Detroit, Mich., a corporation of Michigan Application December 2, 1937, serial No. 177,693

42 Claims. (ci. 51-95i cross-feed slide for supporting the grinding wheel spindle, and hydraulically controlled means for automatically feeding the slide to a predetermined size setting.

Another object-is to provide a new and improved thread grinding machine having a work table translatable by a mechanical drive, a work spindle mounted thereon, a rotary hydraulic motor for operating said drive and said spindle in'` timed relation, and means for compensating for blacklash in said drive.

Another object is to provide a novel grinding wheel support which is adapted to be fed transversely of the work, and which is angularly adjustable to position the grinding wheel 'in accordance with the helix angle of the thread to be ground.

' Arfu'rther object is to provide novel means available at will for imparting'a back-oli reciprocation to the grinding Wheel in timed relation tothe rotation of the work spindle and in any position of the grinding spindle.

Another object is to provide a thread grinding machine having various hydraulic units', and including novel telescoping connections for directing fluid inthe passages to and from said units.-

Still another object is to provide a thread grinding machine having a grinding spindle ad- `instable into diiierent angular positions'relatlve to a horizontal plane.

Further objects and advantages willl become apparent as the description proceeds.

Figure 1 is a front elevational view of the ma- Fig. 6 is a fragmentary `substantially vertical sectional View taken along line 6 6 of Fig. 4, and illustrating the mounting and drive for the head'- stock spindle.

Fig. 7 is a fragmentary horizontal broken sect tional view of the work table illustrating particularly a taper compensating mechanism.

Fig. 8 is a fragmentary elevational View of the taper compensating mechanism.

Fig. 9 is a fragmentary vertical sectional view of the work table, 4and particularly the means for supplying pressure iluid thereto.

Fig. 9a is a fragmentary vertical sectional view taken along line 9ct- 9a oi Fig. e.

Fig. 10 is a fragmentary detail sectional view on an enlarged scale of the feed screw drive for the tool fixture.

Fig. 11 is a fragmentary transverse Vertical sec- 'tional view of-the machine through the work table and the taper compensating mechanism.

Fig. 12 is a fragmentary front elevational view, partially in section. along lines |2--l2 of Fig. 11,

and illustrating the cross feed mechanism.

chine embodying the features of my invention.

Fig. 2 is a left end elevational View oi the machine.

Fig. 3 is a right hand elevational view of the machine.

Fig, 4 is a vertical sectional view of the headstock taken along line 4-4 of Fig. 1.

Fig. 5 is a fragmentary sectional View taken along line 5-5 of Fig. 4,.

Fig. 13 is a fragmentary sectional View of the cross feed mechanism taken substantially along une lS-ls of Fig. i2. l

Fig. 14 is a fragmentary left end View of the machine, partially in section, and illustrating the black-ofi mechanism.

Fig. 15 is a fragmentary vertical of the tool fixture.

Fig. '15a is an axial sectional view of the tool spindle and mounting. v

Fig. 16 is afragmentary detail sectional view taken along line iiii6 of Fig. l5.4 i

Fig. 17 is a fragmentary rear elevational view of the headsto'ck and back-off mechanism.

' Fig. 18 is a fragmentary plan view, partially in horizontal section, of the dressing mechanism for external grinding.

Fig. 1,9 is a detail sectional view taken substantially along line l9--i9 of Fig. 18.

sectional view Fig. 20 is a longitudinal vertical sectional view of the dressing mechanism taken substantially along line 20-20 of Fig. 21.

Fig. 21 is a transverse vertical sectional View of the dressing mechanism taken substantially along line 2i-2i of Fig. 20.

Fig. 22 is a plan view, partially in horizontal section, of a modified form of dressing mechanismadapted for internal grinding.

Fig. 23 isa fragmentary viewof the dressing mechanism illustrated in Fig. 21.

` Figs. 24 and 25 are vertical sectional views taken respectively along lines 24-24 and 25--25 of Fig. 22. l

Fig. 26 is a right end elevational View of the internal grinding spindle drive.

Fig. 27 is a diagrammatic representation of the hydraulic circuits for the machine.

Fig. 28 is a diagrammatic representation of the hydraulicA circuits for the dressing mechanism illustrated in Fig. 18. Y

Fig. 29 is a fragmentary view on an enlarged scale of the table dogs for controlling the machine cycle.

While thev invention is susceptible of various modications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to -be understood' that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawings, the machine, constituting the exemplary embodiment of the invention, comprises a base l which may be of any suitable form, and which preferably is horizontal and angle-shaped, with an elongated front section 2 and a rearwardly extending section 3 at one end. The top of the base section 2 is formed with longitudinal ways 4 provided with antifriction rollers 5 on which a work carriage or table 6 is suitably mounted for reciprocation. A headstock 1, having a power driven work spindle 8, is mounted on the carriage 6 for movement therewith, and is pivotally adjustable to adapt the machine for either cylindrical or taper grinding. A tailstock 9, having a work engaging center I in axial alignment with the spindle `8, maybe adjustably mounted onlongitudinal ways I I formed on the top of an elongated frame extension I2 of the headstock '1. The top of the rear base section 3 is formed with'horizontal ways I3 extending transversely of the ways 4, and on which a tool fixture I4 is mounted for crossfeed and adjustment. The fixture I4 has a power driven spindle l5 which is adapted to support a suitable grinding element or wheel I6 for operative engagement with the work. and which is angularly adjustabfc to compensate for the lead anglo of the work thread when grinding screw elements. A back-off mechanism I'l incorporated in the fixture I4 is selectively available to impart a relief reciprocation to the spindle I5 transversely of the spindle 8 and in timed relation to the rotation of the latter' when relief grinding toothed elements. Mounted on the xture I4 is a dressing mechanism I8 for shapingand truing the-grinding wheel I6 in accordance with the requirements of the work to be ground.

A coolant pump I9, supported by a bracket on the rear of the base l, is driven by a motor 2i, and is adapted to supply coolant under the control of a valve 22 to the grinding wheel I6. The base I is provided in one side with suitable compartments having hinged covers 23 and adapted for the storage of change gears and other accessories. A lubricating pump 24 having an outlet sight gauge 25 and a return sight gauge 26 is mounted in the base I between the-covers 23.

The heads-teck One end of the headstock l (see Figs. l to 6) is formed with a hollow upstanding spindle housing 28 formed internally with a drive compartment 29 and a change gear compartment 3l) separated by an intermediate wallSI. The compartment 29 is closed at the front by a removable cover 32, and the compartment 30 is closed at the end by a removable cover 33. The spindle 8 is journaled adjacent opposite ends in suitable antifriction bearings 34 and 35 mounted respectively in the end walls ofthe compartment 29, and preferably is tubular and of the ange nose end type. Thus,

the outer or operative end 'of the spindle 8 is provided with a 'flange 36 formed with an axial locating bore or recess 31 to mount a work fixture such as a chuck (not shown). The outer end portion of the spindle bore is tapered to form a socket 38 for a sleeve 39 into which a work center 40 may be removablyA inserted. An opening 4| in the cover 33 for the compartment 36 and normally closed by a removable plate 42 affords access to the inner end of the spindle B and permits inserting long work pieces through the spindle.

Rigidly mounted within the drive compartment 29 is a motor 43 which in the present instance is of the rotary hydraulic type. The motor 43 is connected through step pulleys 44 and 45 and a belt 46 to a transverse worm shaft 47 journaled in Iantifriction bearings 4B. An idler pulley 4 9 serves to tension the belt 46. A worm 50 on the shaft 4l meshes with a worm wheel 5I fixed on the'spindle 8 between the bearings 34 and 35 to complete the rotary drive transmission.' The elongated headstock l is mounted on the table 6 for pivotal adjustment'about a vertical axis to permit either cylindrical or taper grinding. More particularly, a tubular pivot sleeve 52 is fixed in the'bottom of the housing 28, and is swiveled in a sleeve 53 in the table 6. Pivotal adjustment of the headstock 'l may be effected by any suitable means operable by a hand knob 54 at the front of the table 6, and the headstock is adapted to be clamped in position of adjustment by suitable gibs 55 and 56 slidably overlying the extreme ends. The gib 55.most remote from the pivotal axis may be provided with suitable graduations for indicating the taper adjustment.

Fluid under pressure is adapted to be. supplied reversibly to the motor 43 through lines 5l and 58. To connect these lines to the motor without necessitating the use of a perishable flexible hose, a manifold plate 59 (sce Figs, 9 and 9a) is bolted to the left end of the base section 2 below the table 6. The plate 59 is formed with three parallel bores 60 opening therethrough longitudinally of the base section 2 to a recess 6I normally closed by a cover 62, and with three passages 63 peripherally intersecting the bores. Two of the passages 63 are connected respectively to the lines 5l and 58 and the third is connected to a drain line 64. Anchored at their outer ends with a uid tight seal to the manifold block 59, in communication respectively with the bores 6D, are three parallel tubes 65 which are plugged or closed at their inner ends and which extend freely through three parallel bores 66 opening longitudinally through Aan elongated manifold block 61 on the undersion of the tube 65. and is formed with a plu` rality of radial ports 69 open to the associated passage 63. The bore 66 in the manifold block 61 is of a larger diameter than the tube 65 to provide t acta-cai a peripheral fluid space. Plain bushings 16 are fixed in the bore 66 adjacent the outer ends and have a close sliding t with the tube 65 to 'provide a guide and a hydraulic seal. Suitable square wire snap rings 16a, are inserted into internal.

grooves 16b in the bore 66 in position to engage the outer ends of the bushings 16 and thereby anchor the latter against the high fluid pressure in the core between the bushings. Additional peripheral seals 11 are provided in lthe ends ofthe bore 66 in axially spaced relation to the bushings 16, and coact with the latter to denne small intermediate annular spaces or chambers 12 adapted yto collect any outwardly leaking fluid. The tube 65 isformed with radial ports 13 which open from the interior thereof to the associated bore 66.

The various chambers 12 at the ends of the bores 66 are connected through passages 14 in the manifold block 61 -to one of the bores 66 in communication with the drain line 64 so as to provide an outlet for the leakage of fiuid. The other two bores 66 are in communication with passages 15 opening through the block .61, the pivot sleeve 52 and the housing 26, respectively, to opposite sides of the motor 43. It will be evident that the various tubes 65 and the block 61, by reason of their telescoping relationship, serveto connect the fluid lines 51 and 58 andthe drain line 64 to the .carriage 6 in any position of reciprocation of the latter, and that the passages 15 in opening through the sleeve 52 permit angular adjustment of the headstock without interfering with the connection of the uid lines 51 and 56 from the carriage to the motor 43.

The table drive Translation of the table l6 (see Figs. 7 and 11) is effected through a nut 16 and a lead screw 11 which are mounted for relative rotation, and of which one is fixed to the base section 2 and the other is movable with the table. In the present instance, the nut 16 '1s supported in a normally fixed position in a sleeve -18 on the upper end of. an upstanding bracket 19 rigidly mounted on a wall 86 within the base section 2, and the screw 11 is supported for a rotary drive on the underside of the table 6. One end of the` screw 11 is freely'splined for relative axial adjustment in a sleeve 81 rotatably mounted in antifriction bearings 82 confined in a lug 63 on the side t of the manifold block 61. The sleeve 81 is operatively connected for rotation in timed relation to the work spindle 8. In lthe present instance, the drive connection (see Figs. 4, and 6) includes a gear B4 fixed on the inner end of the spindle 6 Within the gear compartment 36 of the headstock housing 28. The gear 64 is connected through suitable change gears 85` to a shaft 66 journaled in the wall 31. The change gears 85 are adjustably and removably mounted on a quadrant 81 -pivoted on the shaft 86 and adapted to be clamped vto the wall 31 imposition of adjustment by means of a bolt 68.- Bevel gears 89 serve to connect the shaft 86 to a verticalshaft 96 extending downwardly coaxially through the pivot sleeve 52 and supported therein by suitable antifriction bearings 91. The lower end of the shaft 96 is connected through bevel gears 92 to the sleeve 81, thereby completing the drive to the lead screw 11. By proper selection of the change gears 65, the relative speed and relative direction of rotation of the spindle 6 and the table lead screw 11 may be varied as required.

The bottom ofthe gear compartment 36 constitutes a reservoir adapted to contain a lubri- '.162 and cant for the gearing therein. Anoil pump 93 is mounted in the bottom of the compartment 36,

and is driven by a cam 94 on the spindle 8. Thev pump 93 has an intake 95 below the oil level, and an outlet line 96 discharging in the top of the compartment above the gearing. 1

The right end of the lead screw 11 is adjustably anchoredin a xed axial position relative to the table 6. As herein shown, the right end shaft extension of the lead screw 11 extends slidablyvand rotatably through an elongated bearing sleeve 911 which is secured for axial adjustment in a lug 98 on the underside ofthe table 6. A backlash compensating device 99 is mounted on the sleeve 91, and takes the end thrust of the lead screw 11. Preferably, the device 99 is selectively operable to'cornpensate for backlash in either direction between the nut 16 and the screw 11 and in the gear drive.

The backlash device 99 comprises a cylinder 166 which is mounted at one end on a flange 16| on the sleeve 91, andwhich has connections at opposite ends withv pressure fluid supply lines 163. A piston 164 is reciprocable in the cylinder 166, and is connected to the shaft extension of the lead screw 11. In the present instance, the connection comprises `acollar 165 secured tothe screw '11, and retained for rotation between antifriction end-thrust bearings 166 in the piston 1611. An adjustment screw 161 is threaded through atubular extension 168 on the closed outer end Aof the cylinder 166, and has a stop 169 on the inner end disposed for engagement by the piston. 164 to limit the stroke or range of movement of the latter` The adjustment screw 161 is placed under africtional tension load to eliminate lost motion by a nut 116 threaded thereon within an axial recess 111 in the outer` end of the tubular extension 166 and urged outwardly by coil compression spring means 112. A hand knob 113 is xed on the outer end of the screw 161. `An indicator 161e is mounted on the cylinder 166 of the device 66 and coacts with a bracket 161D on the lug 68 to facilitate adjustment of the range of movement oi the piston 166 by means of the screw |61. This indicator also facilitates accurate adjustment to pickup previously ground threads for removing a very small amount of stock. In use, the stop 169 is so positioned by adjustment of the screw |61 with the aid of theindicator I61a that the stroke ofthe piston 164 equals the total backlash from the spindle 6 to the screw 11, including the backlash in the gearing 86 fand 92 and the backlash between the nut 16 and the screw 11 and between the nut '16 andthe support '16. Hydraulic pressure iiuid is supplied selectively through one or the other of the 1ines'162 and 163 to shift the screw 11 relatively to the table 6 and thereby compensates for the total backlash. Upon reversing the table 6, the take-up on the screw 11 is also vreversed to movethe table ahead in the new direction of travel an adjustable extent corresponding to the backlash so that the cutting path of the grinding wheel 16 will be exactly the same in both directions of table movement. Therefore, it is possible to grind in both directions and to reverse the work drive and table movement at the end of the cut without backing away the wheel, or running the wheel off the end of the work or into an undercut at the end of the threaded portion of the work.

Since the backlash device 96 is an auxiliary mounted on the table 6, the lines 162 and 163 to the cylinder 164 are connected through the 

